This invention relates generally to safe and arm devices, and, more particularly, to a safe and arm device utilized in conjunction with ordnance or other systems which require extremely controllable ignition.
One of the most critical elements in an ordnance is the safe and arming mechanism utilized to maintain the ordnance in a safe condition until proper inputs are received and thereafter to initiate the arming sequence. Generally, receipt of proper input signals results in transforming the safe and arming mechanism from the safe condition into a condition in which a main explosive charge or ignitor can be detonated.
During its lifetime, an ordnance may be subjected to various physical environments which impose severe conditions thereupon. The parameters for many of these environments lead to the design criteria for manufacturing the ordnance. Recent weapon development guidance documents have included specifications for abnormal weapon conditions such as exposure to fire, crushing, severe shock, lightening, flooding, and fragments. One recognition to be gained from such documents is the degree of uncertainty associated with the environment and the difficulty in providing precise and accurate definitions for normal or accident situations. Consequently, there is a general trend toward a complex interrelationship among the major components of a weapon in order to negate accidental or unintentional detonation. Furthermore, it is critical that the detonating systems for such ordnance be isolated from all sources of electrical energy in order to avoid premature detonation.
Many current state of the art art safe and arming mechanisms rely upon either mechanical escapements or electronic timers to provide safe separation timing delays. Further, many mechanisms incorporate or rely upon stored energy for component movement or alignment power. Consequently, the above-mentioned safe and arming mechanisms generally fall short in reliability and predictability of operation as a result of the inflexibility of the mechanical systems and relatively poor timing accuracy involved therewith; the unreliability of mechanical-electrical interlocks as well as the susceptibility of the electrical energy to prematurely or accidentally detonate the ordnance; and the unsatisfactory condition of stored energy which can result in unwanted arming of the ordnance due to inadvertent release of the stored energy.
It is therefore essential that a safe and arm device be devised which not only provides a high degree of certainty in the initiation of an ignitor or detonating charge within an ordnance or the like, but which also is capable of withstanding the effects of abnormal environmental conditions.